The present invention is in the field of glazing units having two, three or more panes that are spaced from one another by means of elongated spacers positioned between the panes.
Insulating glass units and other multi-pane glazing units generally have at least two parallel panes. A peripheral spacer, typically comprising metal, plastic, or both, is provided between the panes adjacent their edges to maintain the panes in a spaced-apart configuration. One or more sealants are usually provided between the panes and the sides of the spacer to seal the edges of the unit. The resulting seal provides resistance to water vapor and gas permeating into the between-pane space. In addition, when the between-pane space is filled with gas, the seal provides resistance to such gas escaping from the between-pane space.
The spacer itself may be provided in hollow, tubular form. In such cases, the spacer may have side walls adhered to the confronting pane surfaces by one or more beads of sealant material, such as polyisobutylene (“PIB”), silicone, or both. Commonly, a particulate desiccant is provided inside the spacer, and the spacer is provided with holes that enable gaseous communication between the interior of the spacer and the between-pane space of the glazing unit. The desiccant can thus extract water vapor from the between-pane space. Desiccant can be provided in other ways; it can be incorporated into the sealant, it can be provided in a matrix form in or on the spacer, etc.
The spacers in glazing units should have good durability, longevity, and lateral compression strength, i.e., good crush resistance. At the same time, these spacers should provide good thermal performance. For example, the spacer should provide a low level of thermal transfer from one side of the glazing unit to the other. Finally, the spacer should have good aesthetics.